Serial consistency levels

This consistency level is for use only with lightweight transactions. Equivalent to
QUORUM.

LOCAL_SERIAL

Same as SERIAL but confined to a single data center. A conditional
write must be written to the commit log and
memtable on a quorum of replica nodes in the same datacenter.

Same as SERIAL but used to maintain consistency locally (within the
single local datacenter). Equivalent to LOCAL_QUORUM.

For local consistency, which enforces serialization within the local datacenter, use:

LOCAL_SERIAL for LWT reads.

LOCAL_QUORUM and LOCAL_SERIAL for LWT writes.

For global consistency, which enforces serialization across multiple datacenters, use:

SERIAL for LWT reads.

QUORUM and SERIAL for LWT writes.

Background information: The SERIAL consistency level defines the serial
consistency level for the Paxos consensus of lightweight transactions. The learn phase uses a
normal consistency level to define which read operations will be guaranteed to complete
immediately if lightweight writes are occurring. The SERIAL consistency level
is ignored for any query that is not a conditional update.